Process for treatment of gases

ABSTRACT

Hydrogen sulfide and/or carbonyl sulfide in a gas which does not substantially contain oxygen can easily be removed from the gas by contacting the gas with an activated carbon containing (1) a copper compound and (2) an alkali metal compound and/or alkaline earth metal compound at a temperature of not higher than 150° C.

This invention relates to a process for treatment of gases, which is useful for removal of hydrogen sulfide and carbonyl sulfide in from inert or reducing gases.

Sulfur comounds such as hydrogen sulfide and carbonyl sulfide are contained in carbon dioxide gas for beverages, coke furnace gas, blast furnace gas, converter gas, thermal cracking gas of petroleum fractions, natural gas, etc. Since these sulfur compounds, even in trace amounts, present characteristic bad smell andcan produce catalyst poisoning effect, they often give rise to various problems such as in carbonation of beverage mixtures and chemical reactions.

In order to remove these sulfur compounds, there have been proposed processes comprising washing with chemical solutions such as alkali solutions and alkanolamine solutions, removal processes by adsorption utilizing iron oxides, zinc oxide, activated carbon, etc. and the like. However, these processes exhibit inferior removal efficiency and encounter difficulties particularly in the removal of carbonyl sulfide.

The present inventors, in view of such circumstances, conducted extensive investigation, and as a result, found that incorporation into activated carbon of a copper compound, and an alkali metal compound and/or an alkaline earth metal compound led to highly efficient removal of hydrogen sulfide and carbonyl sulfide in gases. This finding has culminated in the completion of this invention.

Thus, this invention is concerned with a process for treatment of a gas containing hydrogen sulfide and/or carbonyl sulfide (hereinafter referred to as "sulfur compounds") but not substantially containing oxygen, which comprises contacting the gas with activated carbon (hereinafter referred to as "activated carbon containing metal compound") containing (1) a copper compound and (2) an alkali metal compound and/or an alkaline earth metal compound (alkali metal compound and/or alkaline earth metal compound are collectively or independently referred to hereinafter as "second metal compound") at a temperature of not higher than 150° C., whereby sulfur compounds are removed from the gas.

The activated carbon, which is useful in this invention, may be any activated carbon which is manufactured by known processes utilizing coal, coke, charcoal, coconut shells, resins, etc. as raw material and shows a specific surface area of 200 to 2000 m² /g. The activated carbon is used in a suitable shape, which varies with the intended process for treatment of gases, such as spherical beads, cylindrical pellets, crushed pieces, powder and treadlike pieces.

Examples of the copper compounds used in the present invention include oxides, hydroxides, and salts with inorganic acids (such as carbonates, basic carbonates, nitrates, sulfates, phosphates and halides) or with organic acids (e.g. carboxylates such as formates, acetates, oxalates, etc.).

Examples of the alkali metal compounds include compounds of Li, Na, K, Rb and Cs such as hydroxides, their inorganic salts exemplified by hydrogen carbonates, carbonates, nitrates, borates, silicates, sulfates, halides, etc., and their salts with organic acids, typified by formates, acetates, oxalates, citrates, tartrates, benzoates, phenolates, sulfonates, etc.

Examples of the alkaline earth metal compounds include compounds of Be, Mg, Ca, Sr and Ba, such as oxides and hydroxides, salts with inorganic acids, exemplified by carbonates, nitrates, sulfates, phosphates, halides, etc., and salts with organic acids, typified by formates, acetates, oxalates, etc.

The activated carbon containing metal compounds used in the present invention may contain both of the alkali metal compound and the alkaline earth metal compound.

The contents of the copper compound and the second metal compound in the activated carbon containing metal compounds are 0.1 mg atom to 3.0 mg atom as copper per g of activated carbon, preferably 0.2 mg atom to 2.0 mg atom, and 0.1 mg atom to 5.0 mg atom as alkali metal or as alkaline earth metal per g of activated carbon, preferably 0.2 mg atom to 4.0 mg atom, respectively. In case the activated carbon containing metal compound is one containing both of the alkali metal compound and the alkaline earth metal compound, the amount of one of the second metal compounds is 0.1 mg atom to 5.0 mg atom as metal per g of activated carbon, preferably 0.2 mg atom to 4.0 mg atom, and the amount of the other second metal compound is also 0.1 mg atom to 5.0 mg atom as metal per g of activated carbon, preferably 0.2 mg atom to 4.0 mg atom.

The activated carbon containing metal compounds may contain as a third component a compound of at least one kind of metal (hereinafter referred to as "third metal compound") selected from the group consisting of aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, zinc, cadmium and lead, and the presence of the third metal compound highly improves the removal efficiency for sulfur compounds.

Examples of the third metal compounds include oxides, hydroxides, salts with inorganic acids, exemplified by carbonates, hydrogencarbonates, nitrates, borates, silicates, sulfates, phosphates, halides, etc., ammonium salts and salts with organic acids typified by formates, acetates, oxalates, citrates, etc.

In case the third metal compound is further incorporated into the activated carbon containing metal compounds, the content of the third metal compound in the activated carbon is 0.1 to 5.0 mg atom as metal per g of activated carbon, preferably 0.2 to 4.0 mg atom.

The activated carbon containing metal compound according to this invention is prepared for example by the following processes:

A. In case of the preparation of the activated carbon containing a copper compound and a second metal compound;

(1) A process which comprises adding a copper compound and a second metal compound to a raw material for activated carbon and effecting carbonization and activation by a conventional method,

(2) A process which comprises adding a copper compound to a raw material for activated carbon, effecting carbonization/activation by a conventional method, admixing the resultant activated carbon with a second metal compound, and drying or calcining the mixture, if necessary,

(3) A process which comprises adding a second metal compound to a raw material for activated carbon, effecting carbonization/activation by a conventional method, admixing the resultant activated carbon with a copper compound, and drying or calcining the mixture, if necessary,

(4) A process which comprises admixing activated carbon simultaneously with a copper compound and a second metal compound, and drying or calcining the mixture, if necessary,

(5) A process which comprises admixing activated carbon with a copper compound, drying or calcining the mixture, and admixing with a second metal compound, followed by drying or calcining, if necessary, and

(6) A process which comprises admixing activated carbon with a second metal compound, drying or calcining the mixture, and further admixing with a copper compound, followed by drying or calcining, if necessary.

B. In case of the preparation of the activated carbon containing both an alkali metal compound and an alkaline earth metal compound as the second metal compound;

(1) A process which comprises adding a copper compound, an alkaline earth metal compound and an alkali metal compound to a raw material for activated carbon, and effecting carbonization/activation by a conventional method,

(2) A process which comprises adding a copper compound to raw material for activated carbon, effecting carbonization/activation by a conventional method, admixing the resultant activated carbon with an alkaline earth metal compound and an alkali metal compound, separately, and drying or calcining the mixture, if necessary,

(3) A process which comprises adding an alkaline earth metal compound to a raw material for activated carbon, effecting carbonization/activation by a conventional method, admixing to the resultant activated carbon with a copper compound and an alkali metal compound, either simultaneously or separately, and drying or calcining the mixture, if necessary,

(4) A process which comprises adding an alkali metal compound to a raw material for activated carbon, effecting carbonization/activation by a conventional method, admixing the resultant activated carbon with a copper compound and an alkaline earth metal compound, either simultaneously or separately, and drying or calcining the mixture, if necessary,

(5) A process which comprises admixing activated carbon with a copper compound, an alkaline earth metal compound and an alkali metal compound simultaneously, and drying or calcining the mixture, if necessary,

(6) A process which comprises admixing activated carbon with a copper compound, drying or calcining the mixture, admixing it further with an alkaline earth metal compound and an alkali metal compound, either simultaneously or separately, and drying or calcining the mixture, if necessary,

(7) A process which comprises admixing activated carbon with an alkaline earth metal compound, drying or calcining the mixture, and admixing it further with a copper compound and an alkali metal compound, either simultaneously or separately, followed by drying or calcining, if necessary, and

(8) A process which comprises admixing activated carbon with an alkali metal compound, drying or calcining the mixture, and admixing it further with a copper compound and an alkaline earth metal compound, either simultaneously or separately, followed by drying or calcining, if necessary.

C. In case of the preparation of the activated carbon containing a copper compound, a second metal compound and a third metal compound;

(1) A process which comprises adding a copper compound, a second metal compound and a third metal compound to a raw material for activated carbon, and effecting carbonization/activation by a conventional method,

(2) A process which comprises adding a copper compound to a raw material for activated carbon, effecting carbonization/activation by a conventional method, admixing the resultant activated carbon with a second metal compound and a third metal compound, separately, and drying or calcining the mixture, if necessary,

(3) A process which comprises adding a second metal compound to a raw material for activated carbon, effecting carbonization/activation by a conventional method, admixing the resultant activated carbon with a copper compound and a third metal compound, either simultaneously or separately, and drying or calcining the mixture, if necessary,

(4) A process which comprises adding a third metal compound to a raw material for activated carbon, effecting carbonization/activation by a conventional method, admixing the resultant activated carbon with a copper compound and a second metal compound, either simultaneously or separately, and drying or calcining the mixture, if necessary,

(5) A process which comprises admixing activated carbon with a copper compound, a second metal compound and a third metal compound simultaneously, and drying or calcining the mixture, if necessary,

(6) A process which comprises admixing activated carbon with a copper compound, drying or calcining the mixture, admixing it further with a second metal compound and a third metal compound, either simultaneously or separately, and drying or calcining the mixture, if necessary,

(7) A process which comprises admixing activated carbon with a second metal compound, drying or calcining the mixture, and admixing it further with a copper compound and a third metal compound, either simultaneously or separately, followed by drying or calcining, if necessary, and

(8) A process which comprises admixing activated carbon with a third metal compound, drying or calcining the mixture, and admixing it further with a copper compound and a second metal compound, either simultaneously or separately, followed by drying or calcining, if necessary.

In these preparation processes, the procedure of admixing activated carbon with metal compounds is considered to involve impregnating or spraying activated carbon with a solution or suspension of metal compounds in water (inclusive of aqueous acid or alkali solution) or a variety of solvents.

In the above preparation processes, by "drying" is understood a step which comprises evaporating the water or solvent in the admixed activated carbon at a temperature of not higher than about 130° C., and the term "calcining" denotes a step which comprises heating the admixed activated carbon thus dried under an atmosphere of a gas such as an inert gas, carbon dioxide gas, steam and waste combustion gas at a temperature of not lower than about 130° C. to thermally decompose part or all of the metal compounds.

In the above processes, when activated carbon is admixed with compounds other than oxides of the copper, second metal compounds (except alkali metal compounds) and third metal compounds, it is favorable to effect heat treatment such as drying or calcining after the admixing; in cases in which activated carbon is admixed with a copper compound, a second metal compound (except alkali metal compound) and a third metal compound but is not subjected to heat treatment, it is preferred to use oxides of the copper, second metal (except alkali metal) and third metal compounds; when activated carbon is admixed with alkali metal compounds other than hydroxides, carbonates and hydrogen carbonates of alkali metal as the second metal compound, it is advantageous to effect heat treatment such as drying or calcining after the admixing; and in cases in which activated carbon is admixed with alkali metal compounds without subsequent heat treatment, it is favorable to use hydroxides, carbonates or hydrogencarbonates as the alkali metal compound.

The gas not substantially containing oxygen which is useful in this invention includes those having an oxygen concentration of not more than 2 vol.%. These gases may be exemplified by carbon dioxide gas, coke furnace gas, blast furnace gas, converter gas, thermal cracking gas of petroleum fractions, natural gas, etc.

The process of this invention is conducted by contacting the activated carbon containing metal compounds as obtained by the above procedure with a gas containing sulfur compounds. The solid-gas contacting method is by a known means such as the fixed bed, moving bed and fluidized bed, whereby the contacting temperature is not higher than 150° C., preferably 0° to 150° C., and the gas pressure is not higher than 50 kg/cm², preferably 0.1 to 40 kg/cm², with the gas contacting time being 1/10 to 100 seconds as measured at 25° C. and 1 kg/cm², preferably 1/5 to 80 seconds.

The examples described below illustrate this invention more specifically.

EXAMPLE 1

An activated carbon A of 16 to 24 mesh having a B.E.T. specific surface area of 1040 m² /g was sprayed uniformly with a solution of a certain amount each of copper nitrate and nitrate of an alkali metal. 50 ml of the admixed product thus obtained was packed into a 4-cm diameter column made of quartz glass. The column was heated at a heating rate of 2° C./min. While allowing a nitrogen gas to flow therethrough at a linear flow rate of 10 cm/sec., the packed product was calcined at 350° C. for 30 minutes.

The contents of the copper and alkali-metal compounds in the catalyst thus obtained were 0.2 to 2.0 mg atom as copper and 0.2 to 2.0 mg atom as alkali metal per g of activated carbon, respectively.

As a control for reference, the activated carbon was admixed with copper nitrate solely or with nitrate of an alkali metal solely by the same procedure as mentioned above, and was calcined in a nitrogen gas at 350° C. for 30 minutes to prepare a catalyst.

15 ml each of the catalysts thus obtained was packed into a 1.6-cm diameter glass column. A gas of 40° C. containing 12.5 ppm of COS (N₂ -97.5 vol.% and H₂ O-2.5 vol.%) was allowed to pass through the column at a linear flow rate of 40 cm/sec. to conduct a break-through adsorption test on COS. The results are as shown in Table 1.

EXAMPLE 2

A 12 ml portion each of the catalysts A through M of Example 1 was packed into a 1.6 cm diameter glass column. A gas of 25° C. containing 10.0 ppm of H₂ S (N₂ -97.5 vol.% and H₂ O-2.5 vol.%) was passed through the column at a linear flow rate of 40 cm/sec. to conduct a break-through adsorption test on H₂ S. The results are as shown in Table 2.

EXAMPLE 3

A certain amount each of Li₂ CO₃, Na₂ SO₄, K₂ SO₄, Rb₂ SO₄, Cs₂ SO₄, HCOONa, CH₃ COOK and (COONa) was incorporated into a coconut-shell raw material. After being mixed and crushed, the mixture was kneaded with various kinds of pitch, water, etc., and molded into cylindrical pellets of 4 mm diameter. The pellets were carbonized at 650° C. and further steam-activated at 900° C. The resultant activated carbon showed a B.E.T. specific surface area of 1000 to 1100 m² /g and a content of the alkali metal compound of 0.8 to 1.1 mg atom as metal per g of activated carbon, as shown in Table 3.

Various kinds of the activated carbon were crushed and sieved to a uniform grain size of 16 to 24 mesh and each was sprayed with a solution of a certain amount of copper sulfate in water. 50 ml each of the admixed products thus obtained was packed into a 4 cm diameter column made of quartz glass. The column was heated at a heating rate of 2° C./min., while a nitrogen gas was allowed to pass through it at a linear flow rate of 10 cm/sec., and the packed product was calcined at 350° C. for 30 minutes. The contents of the copper compound in the resultant catalysts were 1.0 mg atom as metal per g of activated carbon.

15 ml each of the catalysts N through U thus obtained was packed into a 1.6-cm diameter glass column, and a gas of 40° C. containing 12.5 ppm of COS (N₂ -97.5 vol.% and H₂ O-2.5 vol.%) was passed through the column at a linear flow rate of 40 cm/sec. to conduct a break-through adsorption test on COS. The results are as shown in Table 3.

EXAMPLE 4

A certain amount each of CuO, CuSO₄, (CH₃ COO)₂ Cu, (HCOO)₂ Cu and CuCl₂ was incorporated into a coconut-shell raw material. After being mixed and crushed, the mixture was kneaded with various kinds of pitch, water, etc., and molded into cylindrical pellets of 4-mm diameter. The pellets were carbonized at 650° C. and further steam-activated at 900° C. The resultant activated carbon showed a B.E.T. specific surface area of 1000 to 1100 m² /g and a content of the copper compound of 0.8 to 1.1 mg atom as metal per g of activated carbon.

Various kinds of the activated carbon were crushed and sieved to a uniform grain size of 16 to 24 mesh and each was sprayed with a solution of a certain of an alkali metal compound in water. 50 ml each of the admixed products thus obtained was packed into a 4-cm diameter column made of quartz glass. The column was heated at a heating rate of 2° C./min., while a nitrogen gas was allowed to pass through it at a linear flow rate of 10 cm/sec, and the packed material was burnt at 300° C. for 30 minutes. The contents of the alkali metal compounds in the resultant catalysts were 1.0 mg atom as metal per g of activated carbon.

15 ml each of the catalysts V through Z thus obtained was packed into a 1.6 cm diameter glass column, and a gas of 40° C. containing 12.5 ppm of COS (N₂ -97.5 vol.% and H₂ O-2.5 vol.%) was passed through the column at a linear flow rate of 40 cm/sec. to conduct a break-through adsorption test on COS. The results are as shown in Table 4.

EXAMPLE 5

A 15 ml portion each of the catalysts F and I of Example 1 was packed into a 1.6 cm diameter glass column, and a gas containing 12.5 ppm of COS (CO-97.5 vol.% and H₂ O-2.5 vol %) was passed through the column at temperatures of 25°, 60°, 80° and 120° C. (in all cases, the linear flow rate of the gas was maintained at 40 cm/sec. as converted to 25° C.).

The COS concentrations in the gases withdrawn at the inlet and outlet of the column were measured by means of FPD gas chromatography, and the COS removal ratios were determined. The results are as shown in Table 5.

                                      TABLE 1                                      __________________________________________________________________________                  Kind and                                                                              Percent removal of COS at the                              Amount of    amount of                                                                             time points shown below (%)                                      copper alkali metal                                                                          15 hrs.                                                                            25 hrs.                                                                            50 hrs.                                                                            75 hrs.                                                                            100 hrs.                                   Catalyst                                                                             (mg-atom/g)                                                                           (mg-atom/g)                                                                           later                                                                              later                                                                              later                                                                              later                                                                              later                                      __________________________________________________________________________     A (control)                                                                          0      0       0   0   0   0   0                                         B (control)                                                                          2.00   0       98  68  8   0   0                                         C (control)                                                                          0      K-2.0  100  50  0   0   0                                         D (present                                                                           0.2    K-1.0  100 100  18  8   1                                         invention)                                                                     E (present                                                                           0.5    K-1.0  100 100  49 10   3                                         invention)                                                                     F (present                                                                           1.0    K-1.0  100 100 100 97  82                                         invention)                                                                     G (present                                                                           2.0    K-1.0  100 100 100 99  90                                         invention)                                                                     H (present                                                                           1.0    K-0.2  100 100  92 68  36                                         invention)                                                                     I (present                                                                           1.0    K-0.5  100 100 100 90  73                                         invention)                                                                     J (present                                                                           1.0    Li-0.5 100 100  85 63  54                                         invention)                                                                     K (present                                                                           1.0    Na-0.5 100 100  94 78  45                                         invention)                                                                     L (present                                                                           1.0    Rb-0.5 100 100 100 90  79                                         invention)                                                                     M (present                                                                           1.0    Cs-0.5 100 100 100 85  70                                         invention)                                                                     __________________________________________________________________________

                                      TABLE 2                                      __________________________________________________________________________                  Kind and                                                                              Percent removal of H.sub.2 S at the                        Amount of    amount of                                                                             time points shown below (%)                                      copper alkali metal                                                                          50 hrs.                                                                            100 hrs.                                                                            150 hrs.                                                                            200 hrs.                                                                            250 hrs.                                Catalyst                                                                             (mg-atom/g)                                                                           (mg-atom/g)                                                                           later                                                                              later                                                                               later                                                                               later                                                                               later                                   __________________________________________________________________________     A (control)                                                                          0      0       0   0    0    0    0                                      B (control)                                                                          2.0    0      100  77   38   9    0                                      C (control)                                                                          0      K-2.0  100  58   5    0    0                                      D (present                                                                           0.2    K-1.0  100 100   83  64   42                                      invention)                                                                     E (present                                                                           0.5    K-1.0  100 100  100  93   81                                      invention)                                                                     F (present                                                                           1.0    K-1.0  100 100  100  97   92                                      invention)                                                                     G (present                                                                           2.0    K-1.0  100 100  100  98   95                                      invention)                                                                     H (present                                                                           1.0    K-0.2  100 100   99  92   79                                      invention)                                                                     I (present                                                                           1.0    K-0.5  100 100  100  95   90                                      invention                                                                      J (present                                                                           1.0    Li-0.5 100 100   90  83   69                                      invention)                                                                     K (present                                                                           1.0    Na-0.5 100 100   95  88   75                                      invention)                                                                     L (present                                                                           1.0    Rb-0.5 100 100  100  93   89                                      invention)                                                                     M (present                                                                           1.0    Cs-0.5 100 100  100  89   80                                      invention)                                                                     __________________________________________________________________________

                                      TABLE 3                                      __________________________________________________________________________                 Kind of alkali Percent removal of COS                                          metal salt and at the time points shown                            BET specific                                                                               amount of alkali                                                                       Amount of                                                                             below (%)                                                surface area                                                                          metal   copper 10 hrs.                                                                            25 hrs.                                                                            50 hrs.                                                                            100 hrs.                                Catalyst                                                                            (m.sup.2 /g)                                                                          (mg-atom/g)                                                                            (mg-atom/g)                                                                           later                                                                              later                                                                              later                                                                              later                                   __________________________________________________________________________     N    1050   Li.sub.2 CO.sub.3 -0.85                                                                1.0    100 100 78  65                                      O    1100   Na.sub.2 CO.sub.3 -0.98                                                                1.0    100 100 80  68                                      P    1010   K.sub.2 SO.sub.4 -0.94                                                                 1.0    100 100 95  79                                      Q    1090   Rb.sub.2 SO.sub.4 -1.05                                                                1.0    100 100 93  84                                      R    1050   Cs.sub.2 SO.sub.4 -1.00                                                                1.0    100 100 89  70                                      S    1100   HCOONa-0.93                                                                            1.0    100 100 78  63                                      T    1080   CH.sub.3 COOK-0.89                                                                     1.0    100 100 93  84                                      U    1020   (COONa).sub.2 -1.03                                                                    1.0    100 100 75  60                                      __________________________________________________________________________

                                      TABLE 4                                      __________________________________________________________________________                 Kind of copper                                                                           Kind of alkali                                                                         Percent removal of COS                                       compound and                                                                             metal salt and                                                                         at a time point shown                            BET specific                                                                               amount of amount of alkali                                                                       below (%)                                             surface area                                                                          copper    metal   10 hrs.                                                                            25 hrs.                                                                            50 hrs.                                                                            100 hrs.                             Catalyst                                                                            (m.sup.2 /g)                                                                          (mg-atom/g)                                                                              (mg-atom/g)                                                                            later                                                                              later                                                                              later                                                                              later                                __________________________________________________________________________     V    1050   CuO-0.95  LiNO.sub.3 -1.0                                                                        100 100 83  72                                   W    1010   CuSO.sub.4 -1.10                                                                         NaNO.sub.3 -1.0                                                                        100 100 90  81                                   X    1070   (CH.sub.3 COO).sub.2 Cu-0.91                                                             KNO.sub.3 -1.0                                                                         100 100 98  83                                   Y    1100   (HCOO).sub.2 Cu-1.00                                                                     RbNO.sub.3 -1.0                                                                        100 100 90  75                                   Z    1050   CuCl.sub.2 -0.88                                                                         CsNO.sub.3 -1.0                                                                        100 100 85  71                                   __________________________________________________________________________

                  TABLE 5                                                          ______________________________________                                                           Percent removal of COS at                                                      the time point shown                                         Contacting        below (%)                                                    temperature       10 hrs.  25 hrs.                                                                              50 hrs.                                                                               100 hrs.                               (°C.)                                                                            Catalyst later    later later  later                                  ______________________________________                                         25       F        100      100    95    88                                              I        100      100    84    80                                     60       F        100      100   100    95                                              I        100      100   100    89                                     80       F        100      100   100    98                                              I        100      100   100    88                                     120      F        100      100   100    98                                              I        100      100   100    75                                     ______________________________________                                    

EXAMPLE 6

The activated carbon A of 16 to 24 mesh having a B.E.T. surface area of 1040 m² /g was sprayed uniformly with a solution in water of the two conponents (i.e. copper nitrate and nitrate of an alkaline earth metal), or the three components (i.e., copper nitrate, an alkaline earth metal compound and a third metal compound or alkali metal compound (nitrate)), 50 ml of the resultant admixed product was packed into a 4 cm diameter column made of quartz glass. The column was heated at a heating rate of 5° C./min., while a nitrogen gas was allowed to pass through it at a linear flow rate of 10 cm/sec., and the packed product was calcined at 300° C. for 30 minutes.

The contents of the copper compound, alkaline earth metal compound, alkali metal and third metal compound in the catalysts thus obtained were all 0.2 to 2.0 mg atom as metal per 1 g of activated carbon, as shown in Table 6.

As the control the activated carbon was admixed with copper nitrate, nitrate of an alkaline earth metal or a third metal compound alone, respectively, by the same procedure as mentioned above, and the admixed products were calcined in a nitrogen gas at 300° C. for 30 minutes to prepare the catalysts.

15 ml each of the catalysts a through j (controls) and 1 to 47 thus obtained was packed into a 1.6 cm diameter glass column, and a gas of 50° C. containing 12.5 ppm of COS (N₂ -97.5 vol.%, H₂ O-2.5 vol.%) was passed through it at a linear flow rate of 40 cm/sec to conduct a break-through adsorption test on COS. The results are as shown in Table 6.

EXAMPLE 7

A 12 ml portion each of the catalysts a through j (controls) and 1 through 47 of Example 6 was packed into a 1.6 cm diameter glass column, and a gas of 30° C. containing 10.0 ppm of H₂ S (N₂ -97.5 vol.%, H₂ O-2.5 vol.%) was passed through it at a linear flow rate of 40 cm/sec. to conduct a break-through adsorption test on H₂ S. The results are as shown in Table 7.

EXAMPLE 8

A certain amount each of an alkaline earth metal compound and alkali metal compound or a third metal compound were added to a coconut-shell raw material. After being mixed and crushed, the mixture was kneaded with various kinds of pitch, water, etc., and molded into cylindrical pellets of 4 mm diameter. These pellets were carbonized at 650° C. and further steam-activated at 900° C. Various kinds of the resultant activated carbon showed a B.E.T. specific surface area of 950 to 1150 m² /g, with their contents of the alkaline earth metal and third metal compounds being all within the range of 0.8 to 1.1 mg atom per g of activated carbon, as shown in Table 8.

Various kinds of such activated carbon were crushed and sieved to a uniform grain size of 16 to 24 mesh and sprayed with a solution of a certain amount of copper acetate in 2% aqueous acetic acid. 50 ml of each of the admixed products thus obtained was packed into a 4 cm diameter column made of quartz glass. The column was heated at a heating rate of 5° C./min., while a nitrogen gas was allowed to pass through it at a linear flow rate of 10 cm/sec., and the packed product was calcined at 300° C. for 30 minutes. The content of the copper compound in the catalyst was 1.0 mg atom per g of activated carbon.

15 ml each of the catalysts, 48 through 76 thus obtained was packed into a 1.6 cm diameter glass column, and a gas of 50° C. containing 12.5 ppm of COS (CO-97.5 vol.% and H₂ O-2.5 vol.%) was passed through it at a linear flow rate of 40 cm/sec. to conduct a break-through adsorption test on COS. The results are as shown in Table 8.

EXAMPLE 9

A 15 ml portion of each of the catalysts 3, 9, 13, 20, 30 and 37 of Example 6 was packed into a 1.6 cm diameter glass column, and a gas containing 12.5 ppm of COS (N₂ -97.5 vol.% and H₂ O-2.5 vol.%) was passed through it at 25°, 60°, 80° and 120° C., respectively (in every case, a gas linear flow rate was maintained at 40 cm/sec. as measured at 25° C.).

The COS concentrations at the outlet and inlet of the column were measured by means of FPD gas chromatography to determine the COS removal rates at certain points of time. The results are as shown in Table 9.

                                      TABLE 6                                      __________________________________________________________________________                 Kind and                                                                              Kind and                                                                              Percent removal of                                               amount of                                                                             amount of                                                                             COS at the time point                                Amount of   alkaline                                                                              alkali metal                                                                          shown below (%)                                           copper earth metal                                                                           or third metal                                                                        25 hrs.                                                                            50 hrs.                                                                            75 hrs.                                                                            100 hrs.                                 Catalyst                                                                            (mg-atom/g)                                                                           (mg-atom/g)                                                                           (mg-atom/g)                                                                           later                                                                              later                                                                              later                                                                              later                                    __________________________________________________________________________     control                                                                        a    0      0      0       0   0   0   0                                       b    200    0      0       90  18  0   0                                       c    0      Mg-2.0 0       35  0   0   0                                       d    0      0      K-2.0   73  0   0   0                                       e    0      Mg-1.0 K-2.0   78  0   0   0                                       f    0      Mg-1.0 Al-1.0  40  3   0   0                                       g    0      Mg-1.0 Cr-1.0  60  11  0   0                                       h    0      Mg-1.0 Fe-1.0  48  15  0   0                                       i    0      Mg-1.0 Zn-1.0 100  48 18   4                                       j    0      Mg-1.0 Cd-1.0 100  40 10   0                                       present                                                                        invention                                                                       1   0.2    Mg-1.0 0      100  98 58  10                                        2   0.5    Mg-1.0 0      100 100 88  23                                        3   1.0    Mg-1.0 0      100 100 90  31                                        4   2.0    Mg-1.0 0      100 100 95  45                                        5   1.0    Mg-0.2 0      100  99 60  35                                        6   1.0    Mg-0.5 0      100 100 75  55                                        7   1.0    Be-1.0 0      100 100 70  30                                        8   1.0    Ca-1.0 0      100 100 68  25                                        9   1.0    Sr-1.0 0      100 100 88  32                                       10   1.0    Ba-0.5 0      100 100 85  24                                       11   0.2    Mg-0.5 K-1.0  100 100 100 89                                       12   0.5    Mg-0.5 K-1.0  100 100 100 95                                       13   1.0    Mg-0.5 K-1.0  100 100 100 98                                       14   2.0    Mg-0.5 K-1.0  100 100 100 100                                      15   1.0    Mg-0.5 Li-0.2 100 100 100 99                                       16   1.0    Mg-0.5 Na-0.5 100 100 100 98                                       17   1.0    Mg-0.5 Rb-1.0 100 100 100 98                                       18   1.0    Mg-0.2 Cs-1.0 100 100 100 100                                      19   1.0    Be-1.0 Na-1.0 100 100 100 96                                       20   1.0    Sr-0.5 Na-1.0 100 100 100 99                                       21   1.0    Ba-0.5 Na-1.0 100 100 100 95                                       22   1.0    Mg-1.0 Pb-1.0 100 100 100 85                                       23   1.0    Mg-1.0 Ti-1.0 100 100 100 59                                       24   1.0    Mg-0.5 Al-0.5 100 100 99  60                                       25   1.0    Mg-0.5 Cr-0.5 100 100 100 75                                       26   1.0    Mg-0.5 Mn-0.5 100 100 94  70                                       27   1.0    Mg-0.5 Fe-0.5 100 100 90  75                                       28   1.0    Mg-0.5 Co-0.5 100 100 99  70                                       29   1.0    Mg-0.5 Ni-0.5 100 100 98  53                                       30   1.0    Mg-0.5 Zn-0.5 100 100 100 98                                       31   1.0    Mg-0.5 Cd-0.5 100 100 90  63                                       32   1.0    Mg-0.5 Pb-0.5 100 100 100 53                                       33   1.0    Mg-0.5 Ti-0.5 100 100 91  41                                       34   1.0    Mg-0.5 V-0.5  100 100 95  48                                       35   1.0    Ca-0.5 Al-0.5 100 100 98  70                                       36   1.0    Ca-0.5 Cr-0.5 100 100 100 64                                       37   1.0    Ca-0.5 Zn-0.5 100 100 100 92                                       38   1.0    Ca-0.5 Pb-0.5 100 100 100 70                                       39   1.0    Ca-0.5 Cd-0.5 100 100 100 75                                       40   1.0    Be-0.5 Al-0.5 100 100 81  38                                       41   1.0    Be-0.5 Cr-0.5 100 100 94  54                                       42   1.0    Sr-0.5 Zn-0.5 100 100 100 90                                       43   1.0    Sr-0.5 Cd-0.5 100 100 92  50                                       44   1.0    Ba-0.5 V-0.5  100 100 100 69                                       45   1.0    Ba-0.5 Ti-0.5 100 100 85  41                                       46   0.2    Ca-1.0 Al-0.5 100 100 88  40                                       47   0.5    Ca-1.0 Al-0.5 100 100 85  71                                       __________________________________________________________________________

                  TABLE 7                                                          ______________________________________                                         Percent removal of H.sub.2 S at the                                            time point shown below (%)                                                            50 hrs.  100 hrs. 150 hrs.                                                                               200 hrs.                                                                              250 hrs.                               Catalyst                                                                              later    later    later   later  later                                  ______________________________________                                         control                                                                        a       0        0        0       0      0                                     b      100       79       39      13     0                                     c       95       32       0       0      0                                     d      100       58       5       0      0                                     e      100       69       15      0      0                                     f      100       30       0       0      0                                     g      100       45       11      0      0                                     h      100       25       0       0      0                                     i      100       64       14      0      0                                     j      100       48       6       0      0                                     present                                                                        invention                                                                       1     100      100       98      69     39                                     2     100      100      100      95     83                                     3     100      100      100      95     86                                     4     100      100      100     100     98                                     5     100      100       90      81     65                                     6     100      100       98      93     86                                     7     100      100       90      83     69                                     8     100      100       98      81     73                                     9     100      100      100      95     89                                    10     100      100       99      98     84                                    11     100      100      100     100     98                                    12     100      100      100     100     98                                    13     100      100      100     100    100                                    14     100      100      100     100    100                                    15     100      100      100     100    100                                    16     100      100      100     100    100                                    17     100      100      100     100    100                                    18     100      100      100     100     99                                    19     100      100      100     100    100                                    20     100      100      100     100    100                                    21     100      100      100     100    100                                    22     100      100      100      95     89                                    23     100      100      100      91     85                                    24     100      100      100     100     90                                    25     100      100      100     100     98                                    26     100      100      100     100     95                                    27     100      100      100     100     98                                    28     100      100      100      95     80                                    29     100      100      100      91     78                                    30     100      100      100     100    100                                    31     100      100      100     100    100                                    32     100      100      100     100    100                                    33     100      100      100      95     81                                    34     100      100      100     100    100                                    35     100      100      100     100     98                                    36     100      100      100     100    100                                    37     100      100      100     100    100                                    38     100      100      100     100     83                                    39     100      100      100     100     86                                    40     100      100      100      98     94                                    41     100      100      100      92     88                                    42     100      100      100     100    100                                    43     100      100      100     100    100                                    44     100      100      100     100    100                                    45     100      100      100     100     98                                    46     100      100      100      86     75                                    47     100      100      100      94     91                                    ______________________________________                                    

                                      TABLE 8                                      __________________________________________________________________________              Kind of   Kind of third                                                        alkaline earth                                                                           metal compound                                              BET      metal salt                                                                               or alkali                                                                               Amount of Percent removal of COS                   specific and amount                                                                               metal compound                                                                          copper    at the time point shown                  surface  alkaline earth                                                                           and amount of                                                                           compound  below (%)                                     area                                                                               metal     the metal                                                                               (as metal)                                                                               25 hrs.                                                                            50 hrs.                                                                            75 hrs.                                                                            100 hrs.                     Catalyst                                                                            (m.sup.2 /g)                                                                       (mg-atom/g)                                                                              (mg-atom/g)                                                                             (mg-atom/g)                                                                              later                                                                              later                                                                              later                                                                              later                        __________________________________________________________________________     48   1100                                                                               Be(NO.sub.3).sub.2 -1.0                                                                   --      CuO-0.89  100  95 76  49                           49   1060                                                                               Mg(NO.sub.3).sub.2 -1.0                                                                   --      CuSO.sub.4 -0.98                                                                         100 100 80  45                           50    980                                                                               Ca(NO.sub.3).sub.2 -1.0                                                                   --      (CH.sub.3 COO).sub.2 Cu-1.03                                                             100 100 83  35                           51   1000                                                                               Sr(NO.sub.3).sub.2 -1.0                                                                   --      (HCOO).sub.2 Cu-0.94                                                                     100 100 86  51                           52    970                                                                               Ba(NO.sub.3).sub.2 -1.0                                                                   --      CuCl.sub.2 -1.07                                                                         100  93 61  28                           53    980                                                                               BeCO.sub.3 -0.95                                                                          --      (CH.sub.3 COO).sub.2 Cu-1.0                                                              100  93 58  25                           54   1110                                                                               MgO-0.83   --      (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 75  39                           55    960                                                                               CaO-0.91   --      (CH.sub.3 COO).sub.2 Cu-1.0                                                              100  98 56  16                           56   1050                                                                               SrO-1.05   --      (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 90  63                           57   1140                                                                               Ba(OH).sub.2 -0.98                                                                        --      (CH.sub.3 COO).sub.2 Cu-1.0                                                              100  90 64  43                           58   1000                                                                               MgCl.sub.2 -1.09                                                                          --      (CH.sub.3 COO).sub.2 Cu-1.0                                                              100  93 70  51                           59   1060                                                                               (CH.sub.3 COO).sub.2 Mg-0.94                                                              --      (CH.sub.3 COO).sub.2 Cu-1.0                                                              100  99 85  67                           60    990                                                                               (HCOO).sub.2 Ca-0.87                                                                      --      (CH.sub.3 COO).sub.2 Cu-1.0                                                              100  98 71  43                           61   1120                                                                               BaCO.sub.3 -0.95                                                                         Li.sub.2 CO.sub.3 -0.85                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 91  25                           62   1110                                                                               SrCO.sub.3 -0.82                                                                         Na.sub.2 SO.sub.4 -0.93                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 90  42                           63    980                                                                               BeCO.sub.3 -0.99                                                                         K.sub.2 SO.sub.4 -0.88                                                                  (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 95  53                           64    980                                                                               MgCO.sub.3 -0.92                                                                         Rb.sub.2 SO.sub. 4 -1.01                                                                (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 100 65                           65    960                                                                               (CH.sub.3 COO).sub.2 Sr-0.83                                                             Cs.sub.2 SO.sub.4 -1.00                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 89  31                           66   1100                                                                               MgCO.sub.3 -0.92                                                                         HCOONa-1.09                                                                             (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 96  45                           67   1030                                                                               (HCOO).sub.2 Mg-1.04                                                                     CH.sub.3 COOK-1.10                                                                      (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 100 79                           68   1010                                                                               CaCO.sub.3 -1.00                                                                         (COONa).sub.2 -0.90                                                                     (CH.sub.3 COO).sub.2 Cu-1.0                                                              100  95 81  13                           69    980                                                                               BeCO.sub.3 -0.95                                                                         Al(NO.sub.3).sub.3 -0.5                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100  98 85  49                           70   1110                                                                               MgO-0.83  Cr(NO.sub.3).sub.3 -0.5                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 87  58                           71    960                                                                               CaCO.sub.3 -0.91                                                                         Mn(NO.sub.3).sub.2 -0.5                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 93  60                           72   1050                                                                               SrO-1.05  Fe(NO.sub.3).sub.3 -0.5                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 91  75                           73   1140                                                                               Ba(OH).sub.2 -0.98                                                                       Co(NO.sub.3).sub.2 -0.5                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 78  53                           74   1000                                                                               MgCl.sub.2 -1.09                                                                         Ni(NO.sub.3).sub.2 -0.5                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100  99 73  61                           75   1060                                                                               (CH.sub.3 COO).sub.2 Mg-0.94                                                             Zn(NO.sub.3).sub.2 -0.5                                                                 (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 100 100                          76    990                                                                               (HCOO).sub.2 Ca-0.87                                                                     VOSO.sub.4 -0.5                                                                         (CH.sub.3 COO).sub.2 Cu-1.0                                                              100 100 95  88                           __________________________________________________________________________

                  TABLE 9                                                          ______________________________________                                                          Percent removal of COS at the                                 Contacting       time point shown below (%)                                    Temperature      25 hrs. 50 hrs.                                                                               75 hrs.                                                                              100 hrs.                                 (°C.)                                                                           Catalyst later   later  later later                                    ______________________________________                                         25       3       100      97     83   69                                                9       100      94     80   65                                       60       3       100     100    100   64                                                9       100     100    100   51                                       80       3       100     100    100   86                                                9       100     100    100   73                                       120      3       100     100    100   52                                                9       100     100    100   35                                       25      13       100     100     98   95                                               20       100     100     97   92                                       60      13       100     100    100   100                                              20       100     100    100   100                                      80      13       100     100    100   100                                              20       100     100    100   100                                      120     13       100     100    100   75                                               20       100     100    100   61                                       25      30       100     100     95   88                                               37       100     100    100   95                                       60      30       100     100    100   69                                               37       100     100    100   100                                      80      30       100     100    100   78                                               37       100     100    100   100                                      120     30       100     100    100   51                                               37       100     100    100   68                                       ______________________________________                                    

EXAMPLE 10

The activated carbon A of 16 to 24 mesh having a B.E.T. specific surface area of 1065 m² /g was sprayed evenly with a solution in water of a certain amount each of copper nitrate, nitrate of an alkali metal and nitrate of Al, Cr, Mn, Fe, Co, Ni, Zn, Cd or Pb, titanium sulfate or vanadium sulfate.

50 ml of the resultant admixed product was packed into a 4-cm diameter column made of quartz glass. The column was heated at a heating rate of 5° C./min while a nitrogen gas was allowed to pass through it at a linear flow rate of 10 cm/sec., and the packed product was calcined at 300° C. for 30 minutes.

The content each of the copper compound, alkali metal compound and the compounds of Al, Cr, Mn, Fe, Co, Ni, Zn, Cd, Pb, Ti and V in the catalysts thus obtained were 0.2 to 2.0 mg atom as metal per g of activated carbon, as shown in Table 10.

As the control the activated carbon was admixed by the same procedure as mentioned above with combinations of copper nitrate and nitrate of an alkali metal and a compound of Al, Cr, Mn, Fe, Co, Ni, Zn, Cd, Pb, Ti or V, and the admixed product was calcined in a nitrogen gas at 300° C. for 30 minutes. By this procedure, catalysts were prepared.

15 ml each of the catalysts ○E through ○M thus obtained was packed into a 1.6 cm diameter glass column, and a gas of 50° C. containing 12.5 ppm of COS (N₂ -97.5 vol.% and H₂ O-2.5 vol.%) was passed through it at a linear flow rate of 40 cm/sec to conduct a break-through adsorption test on COS. The results are as shown in Table 10.

EXAMPLE 11

A 12 ml portion each of the catalysts ○E through ○M of Example 10 was packed into a 1.6 cm diameter glass column, and a gas of 25° C. containing 10 ppm of H₂ S (N₂ -97.5 vol.% and H₂ O-2.5 vol.%) was passed through it at a linear flow rate of 40 cm/sec to conduct a break-through adsorption test on H₂ S. The results are as shown in Table 11.

EXAMPLE 12

A certain amount of each of Li₂ CO₃, Na₂ SO₄, K₂ SO₄, Rb₂ SO₄, Cs₂ SO₄, HCOONa, CH₃ COOK and (COONa)₂ was added to a coconut-shell raw material. After being mixed and crushed, the mixture was kneaded with various kinds of pitch, water, etc., and molded into cylindrical pellets of 4 mm diameter. The pellets were carbonized at 650° C. and steam-activated at 900° C.

The activated carbon thus obtained all showed a B.E.T. specific surface area of 950 to 1150 m² /g and a content of an alkali metal compound of 0.4 to 0.6 mg atom as metal per g of activated carbon, as shown in Table 12.

Various kinds of the activated carbon were crushed and sieved to a uniform grain size of 16 to 24 mesh and each was sprayed with a solution in a 2% aqueous nitric acid of the determined amount each of copper nitrate and nitrate of Al, Cr, Mn, Fe, Co., Ni, Zn, Cd or Pb, titanium sulfate or vanadyl sulfate.

50 ml each of the admixed products thus obtained was packed into a 4-cm diameter column made of quartz glass. The column was heated at a heating rate of 5° C./min, while a nitrogen gas was allowed to pass through it at a linear flow rate of 10 cm/sec., and the packed product was calcined at 350° C. for 30 minutes. The content of the copper compound in the resultant catalysts was 1.0 mg atom as metal per g of activated carbon, while the contents of the compounds of Al, Cr, Mn, Fe, Co, Ni, Zn, Cd, Pb, Ti and V were 0.5 mg atom as metal per g of activated carbon.

15 ml each of the catalysts ○N through ○U thus obtained was packed into a 1.6 cm diameter glass column, and a gas of 40° C. containing 12.5 ppm of COS (N₂ -97.5 vol.% and H₂ O-2.5 vol.%) was passed through it to conduct a break-through adsorption test on COS. The results are as shown in Table 12.

EXAMPLE 13

A 15 ml portion each of the catalysts ○G₇ and ○H₃ of Example 10 was packed into a 1.6-cm diameter glass column, and a gas containing 12.5 ppm of COS (N₂ -97.5 vol.% and H₂ O-2.5 vol.%) was passed through the column at 25°, 60°, 80° and 120° C., respectively, to conduct break-through adsorption tests on COS, whereby the gas linear flow rate in every case was maintained at 40 cm/sec as measured at 25° C. The test results are as shown in Table 13.

                                      TABLE 10                                     __________________________________________________________________________                            Kind and                                                                              Percent removal of COS at                                        Kind and                                                                              amount the time point shown below                                Amount of                                                                             amount of                                                                             of third                                                                              (%)                                                       copper alkali metal                                                                          metals 25 hrs.                                                                            50 hrs.                                                                            75 hrs.                                                                            100 hrs.                             Catalyst (mg-atom/g)                                                                           (mg-atom/g)                                                                           (mg-atom/g)                                                                           later                                                                              later                                                                              later                                                                              later                                __________________________________________________________________________      ○E.sub.1   (control)                                                            0      Na-1.0 Al-1.0 49  4   0   0                                     ○E.sub.2   (control)                                                            0      Na-1.0 Cr-1.0 68  15  0   0                                     ○E.sub.3   (control)                                                            0      Na-1.0 Fe-1.0 51  18  3   0                                     ○E.sub.4   (control)                                                            0      Na-1.0 Zn-1.0 100 60  26  11                                    ○E.sub.5   (control)                                                            0      Na-1.0 Cd-1.0 100 55  13  0                                     ○F.sub.1   (present                                                             1.0    Na-1.0 Pb-1.0 100 100 100 77                                   invention)                                                                      ○F.sub.2   (present                                                             1.0    Na-1.0 Ti-1.0 100 100 100 69                                   invention)                                                                      ○G.sub.1   (present                                                             1.0    Na-0.5 Al-0.5 100 100 98  68                                   invention)                                                                      ○G.sub.2   (present                                                             1.0    Na-0.5 Cr-0.5 100 100 100 73                                   invention)                                                                      ○G.sub.3   (present                                                             1.0    Na-0.5 Mn-0.5 100 100 95  63                                   invention)                                                                      ○G.sub.4   (present                                                             1.0    Na-0.5 Fe-0.5 100 100 95  79                                   invention)                                                                      ○G.sub.5   (present                                                             1.0    Na-0.5 Co-0.5 100 100 98  53                                   invention)                                                                      ○G.sub.6   (present                                                             1.0    Na-0.5 Ni-0.5 100 100 96  49                                   invention)                                                                      ○G.sub.7   (present                                                             1.0    Na-0.5 Zn-0.5 100 100 100 70                                   invention)                                                                      ○G.sub.8   (present                                                             1.0    Na-0.5 Cd-0.5 100 100 96  56                                   invention)                                                                      ○G.sub.9   (present                                                             1.0    Na-0.5 Pb-0.5 100 100 100 60                                   invention)                                                                      ○G.sub.10   (present                                                            1.0    Na-0.5 Ti-0.5 100 100 93  48                                   invention)                                                                      ○G.sub.11   (present                                                            1.0    Na-0.5 V-0.5  100 100 98  58                                   invention)                                                                      ○H.sub.1   (present                                                             1.0    K-0.5  Al-0.5 100 100 100 73                                   invention)                                                                      ○H.sub.2   (present                                                             1.0    K-0.5  Cr-0.5 100 100 100 61                                   invention)                                                                      ○H.sub.3   (present                                                             1.0    K-0.5  Zn-0.5 100 100 100 88                                   invention)                                                                      ○H.sub.4   (present                                                             1.0    K-0.5  Pb-0.5 100 100 100 69                                   invention)                                                                      ○H.sub.5   (present                                                             1.0    K-0.5  Cd-0.5 100 100 100 78                                   invention)                                                                      ○I.sub.1   (present                                                             1.0    Li-0.5 Al-0.5 100 100 95  59                                   invention)                                                                      ○I.sub.2   (present                                                             1.0    Li-0.5 Cr-0.5 100 100 98  63                                   invention)                                                                      ○J.sub.1   (present                                                             1.0    Rb-0.5 Zn-0.5 100 100 100 89                                   invention)                                                                      ○J.sub.2   (present                                                             1.0    Rb-0.5 Cd-0.5 100 100 97  54                                   invention)                                                                      ○K.sub.1   (present                                                             1.0    Cs-0.5 V-0.5  100 100 100 78                                   invention)                                                                      ○K.sub.2   (present                                                             1.0    Cs-0.5 Ti-0.5 100 100 94  53                                   invention)                                                                      ○L  (present                                                                    0.2    K-1.0  Al-0.5 100 100 90  40                                   invention)                                                                      ○M  (present                                                                    0.5    K-1.0  Al-0.5 100 100 95  77                                   invention)                                                                     __________________________________________________________________________

                  TABLE 11                                                         ______________________________________                                         Percent removal of H.sub.2 S at the                                            time point shown below (%)                                                              50 hrs. 100 hrs. 150 hrs.                                                                              200 hrs.                                                                              250 hrs.                               Catalyst later   later    later  later  later                                  ______________________________________                                          ○E.sub.1   (control)                                                            100      48       12     0      0                                      ○E.sub.2   (control)                                                            100      69       18     0      0                                      ○E.sub.3   (control)                                                            100      54       4      0      0                                      ○E.sub.4   (control)                                                            100      72       24     0      0                                      ○E.sub.5   (control)                                                            100      60       13     0      0                                      ○F.sub.1   (present                                                             100     100      100     98    90                                     invention)                                                                      ○F.sub.2   (present                                                             100     100      100     95    90                                     invention)                                                                      ○G.sub.1   (present                                                             100     100      100     99    94                                     invention)                                                                      ○G.sub.2   (present                                                             100     100      100    100    92                                     invention)                                                                      ○G.sub.3   (present                                                             100     100      100    100    90                                     invention)                                                                      ○G.sub. 4   (present                                                            100     100      100    100    94                                     invention)                                                                      ○G.sub.5   (present                                                             100     100      100     98    85                                     invention)                                                                      ○G.sub.6   (present                                                             100     100      100     98    89                                     invention)                                                                      ○G.sub.7   (present                                                             100     100      100    100    91                                     invention)                                                                      ○G.sub.8   (present                                                             100     100      100    100    100                                    invention)                                                                      ○G.sub.9   (present                                                             100     100      100    100    100                                    invention)                                                                      ○G.sub.10   (present                                                            100     100      100     98    91                                     invention)                                                                      ○G.sub.11   (present                                                            100     100      100    100    100                                    invention)                                                                      ○H.sub.1   (present                                                             100     100      100    100    95                                     invention)                                                                      ○H.sub.2   (present                                                             100     100      100    100    100                                    invention)                                                                      ○H.sub.3   (present                                                             100     100      100    100    100                                    invention)                                                                      ○H.sub.4   (present                                                             100     100      100    100    94                                     invention)                                                                      ○H.sub.5   (present                                                             100     100      100    100    96                                     invention)                                                                      ○I.sub.1   (present                                                             100     100      100     95    91                                     invention)                                                                      ○I.sub.2   (present                                                             100     100      100     98    92                                     invention)                                                                      ○J.sub.1   (present                                                             100     100      100    100    100                                    invention)                                                                      ○J.sub.2   (present                                                             100     100      100    100    100                                    invention)                                                                      ○K.sub.1   (present                                                             100     100      100    100    100                                    invention)                                                                      ○K.sub.2   (present                                                             100     100      100     99    96                                     invention)                                                                      ○L  (present                                                                    100     100      100     92    85                                     invention)                                                                      ○M  (present                                                                    100     100      100     93    90                                     invention)                                                                     ______________________________________                                    

                                      TABLE 12                                     __________________________________________________________________________              Kind of alkali                                                        B.E.T.   metal salt           Percent removal of                               specific incorporated                                                                           Amount       COS at the time point                            surface  and amount of                                                                          of     Kind and                                                                             shown below (%)                                       area                                                                               alkali metal                                                                           copper amount of                                                                            25 hrs.                                                                            50 hrs.                                                                            75 hrs.                                                                            100 hrs.                             Catalyst                                                                            (m.sup.2 /g)                                                                       (mg-atom/g)                                                                            (mg-atom/g)                                                                           third metal                                                                          later                                                                              later                                                                              later                                                                              later                                __________________________________________________________________________      ○N                                                                          1100                                                                               Li.sub.2 CO.sub.3 -0.45                                                                1.0    Al-0.5                                                                               100 100 93  48                                    ○O                                                                          1050                                                                               Na.sub.2 SO.sub.4 -0.49                                                                1.0    Cr-0.5                                                                               100 100 98  65                                    ○P                                                                           980                                                                               K.sub.2 SO.sub.4 -0.48                                                                 1.0    Mn-0.5                                                                               100 100 95  60                                    ○Q                                                                          1000                                                                               Rb.sub.2 SO.sub.4 -0.51                                                                1.0    Fe-0.5                                                                               100 100 93  63                                    ○R                                                                          1000                                                                               Cs.sub.2 SO.sub.4 -0.55                                                                1.0    Co-0.5                                                                               100 100 100 68                                    ○S                                                                           960                                                                               HCOONa-0.46                                                                            1.0    Ni-0.5                                                                               100 100 96  55                                    ○T                                                                          1080                                                                               CH.sub.3 COOK-0.50                                                                     1.0    Zn-0.5                                                                               100 100 100 56                                    ○U                                                                          1100                                                                               (COONa).sub.2 -0.52                                                                    1.0    V-0.5 100 100 100 49                                   __________________________________________________________________________

                  TABLE 13                                                         ______________________________________                                                           Percent removal of COS at the                                Contacting        time point shown below (%)                                   temperature       25 hrs. 50 hrs.                                                                               75 hrs.                                                                              100 hrs.                                (°C.)                                                                            Catalyst later   later  later later                                   ______________________________________                                         25        ○G.sub.7                                                                        100     100     90   85                                                ○H.sub.3                                                                        100     100    100   92                                      60        ○G.sub.7                                                                        100     100    100   58                                                ○H.sub.3                                                                        100     100    100   100                                     80        ○G.sub.7                                                                        100     100    100   59                                                ○H.sub.3                                                                        100     100    100   100                                     120       ○G.sub.7                                                                        100     100    100   46                                                ○H.sub.3                                                                        100     100    100   65                                      ______________________________________                                     

What is claimed is:
 1. A process for treatment of a gas containing hydrogen sulfide and/or carbonyl sulfide but not substantially containing oxygen, which comprises contacting the gas with activated carbon containing (1) a copper compound and (2) an alkali metal compound and/or an alkaline earth metal compound, at a temperature of not higher than 150° C., whereby hydrogen sulfide and/or carbonyl sulfide are removed from the gas.
 2. A process as claimed in claim 1, wherein the activated carbon contains the copper compound and the alkali metal compound.
 3. A process as claimed in claim 1, wherein the activated carbon contains the copper compound and the alkaline earth metal compound.
 4. A process as claimed in claim 1, wherein the activated carbon contains the copper compound, the alkali metal compound and the alkaline earth metal compound.
 5. A process as claimed in claim 1, wherein the activated carbon contains the compound of at least one metal selected from the group consisting of Al, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Cd and Pd as a third component, together with the copper compound and the alkali metal compound and/or alkaline earth metal compound.
 6. A process as claimed in claim 5, wherein the activated carbon contains the copper compound, the alkali metal compound and the compound of at least one metal selected from the group consisting of Al, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Cd and Pb.
 7. A process as claimed in claim 5, wherein the activated carbon contains the copper compound, the alkaline earth metal compound and the compound of at least one metal selected from the group consisting of Al, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Cd and Pb.
 8. A process as claimed in claim 1, wherein the gas not substantially containing oxygen has an oxygen concentration of not more than 2 vol %.
 9. A process as claimed in claim 1, wherein the gas is contacted with the activated carbon at a temperature of 0° C. to 150° C.
 10. A process as claimed in claim 1, wherein the gas is contacted with the activated carbon for 1/10 to 100 seconds. 